Structural member of a work machine

ABSTRACT

Structural members of work machines experience heavy forces and the structural member must be able to endure such heavy forces, but must also be sufficiently light to prevent the work machine from using most of its available power to manipulate the structural member. The present apparatus facilitates the heavy-duty construction along with a reduced weight by comprising top and bottom portions, a middle portion attached between and substantially perpendicular with the top and bottom portions, and a primary coupling formed at a first-end portion of the structural member and extending from at least one of the top, bottom, and middle portions to define a substantially I-shaped structural member.

TECHNICAL FIELD

[0001] This invention relates generally to a structural member of a work machine and, more particularly, to a particular structure of the structural member.

BACKGROUND

[0002] In work machines, such as backhoe loaders, skid steer loaders, and excavators, substantial forces are transmitted through a member that connects an implement to a frame of the work machine. The member typically includes a boom and a stick, the stick being pivotally attached with the boom. During operation of the work machine, the member experiences heavy forces as the implement penetrates the ground to dig, carries heavy loads from one location to another, or pushes or pulls material. The member, therefore, must be able to endure such heavy forces. The member, however, must also be sufficiently light to prevent the work machine from using most of its available power to manipulate the member. The member, therefore, must have a structural design that combines a heavy-duty construction along with being relatively light weight.

[0003] One known boom design is disclosed in U.S. Pat. No. 6,158,949 issued to Walth et. al. on Dec. 12, 2000. It discloses a boom design having a top boom support structure, a bottom boom support structure, a first lateral boom support structure, and a second lateral boom support structure, which cooperate with each other to define a boom void therein. This boom design requires the attachment of four supporting structures, which creates a heavier boom, increases fatigue due to the additional welding required to manufacture, and is more time consuming to manufacture. This creates a boom design that is expensive to operate due to the additional energy required to manipulate the heavy boom and is more expensive to manufacture due to the additional structures and the additional welding required.

[0004] The present invention is directed to overcoming one or more of the problems as set forth above.

SUMMARY OF THE INVENTION

[0005] In one aspect of the present invention, a structural member of a work machine has first and second-end portions, and comprises, a body having a top portion, a bottom portion, and a middle portion. The top and bottom portions have longitudinal centerlines. The middle portion is positioned between and substantially perpendicular with the top and bottom portions and positioned substantially at the longitudinal centerline of at least one of the top and bottom portions. The structural member further comprises a primary coupling formed with the body at the first-end portion of the structural member and extends from at least one of the top, bottom, and middle portions.

[0006] In another aspect of the present invention, a work machine comprises a frame, a first member, a second member, a primary coupling, and a secondary coupling. The first member has first and second end portions, a top portion having a longitudinal centerline, a bottom portion having a longitudinal centerline, and a middle portion. The middle portion is positioned between and substantially perpendicular with the top and bottom portions and positioned substantially at the longitudinal centerline of at least one of the top and bottom portions. The primary coupling is defined at the first-end portion of the first member for pivotable attachment with the frame, and the secondary coupling is defined at the second-end portion of the first member for pivotable attachment with the second member.

[0007] The present invention is a structural member of a work machine that has first and second-end portions, and comprises, a body having a top portion, a bottom portion, and a middle portion. The top and bottom portions have longitudinal centerlines. The middle portion is positioned between and substantially perpendicular with the top and bottom portions substantially at the longitudinal centerline of at least one of the top and bottom portions. The structural member further comprises a primary coupling formed with the body at the first-end portion of the structural member and extends from at least one of the top, bottom, and middle portions. The positioning of the middle portion between and substantially perpendicular with the top and bottom portions provides sufficient support for the compressive and tensional forces applied to the structural member during normal operation by distributing such forces throughout the structural member. The structural member, therefore, is able to handle heavy-duty applications with a reduced weight configuration.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a side view of a work machine, such as a backhoe loader, incorporating a boom of the present invention;

[0009]FIG. 2 is a perspective view of the boom of FIG. 1 fabricated as a unitary casting; and

[0010]FIG. 3 is an exploded view of an alternate embodiment of the boom of FIG. 1 manufactured from various components.

DETAILED DESCRIPTION

[0011] While the invention is open to various modifications and alternative forms, a specific embodiment thereof has been shown by way of example in the drawings and will herein be described in detail. There is, however, no intent to limit the invention to the particular form disclosed.

[0012] Referring to the drawings, FIG. 1 is a work machine 1, such as a backhoe loader, skid steer loader, or excavator, that has a frame 10, a plurality of wheels 20 supporting the frame 10 against the ground, and an operator's compartment 30 supported on the frame 10 and positioned substantially above the wheels 20 on the rear-end portion of the work machine 1. The work machine 1 further includes a front member 40 and a rear member 50 pivotally attached with the front and rear-end portions of the frame 10, respectively. The front member 40 includes a multi-bar linkage 60 pivotally attached with the front-end portion of the frame 10 and a front implement 70 pivotally attached with the multi-bar linkage 60. The front implement 70 may be a loader bucket, brush, auger, or other suitable worktool. The rear member 50 includes a boom 80 pivotally attached with the rear-end portion of the frame 10, a stick 90 pivotally attached with the boom 80, and a rear implement 100 pivotally attached with the stick 90. The rear implement 100 may be a bucket, a grapple, or any other suitable worktool. The work machine 1 also includes a first hydraulic cylinder 110 that has a first-end portion attached with the boom 80 and a second-end portion attached with the stick 90. A second hydraulic cylinder 120 has a first-end portion attached with the boom 80 and a second-end portion attached with the rear-end portion of the frame 10. It should be understood that the work machine 1 could be of any suitable type that utilizes a boom and not just those enumerated above or the backhoe loader depicted in FIG. 1.

[0013] In FIG. 2, the boom 80 of the work machine 1 is shown in more detail. The boom 80 is made from a unitary casting and includes a body 124 that has a top portion 130, a bottom portion 140, and a middle portion 150. The middle portion 150 is positioned between and substantially perpendicular with a longitudinal centerline 160, 170 of the top and bottom portions 130, 140 to define a substantially I-shaped beam. It should be understood that the middle portion 150 could a variety of other shapes, such as V, W, M, or any other shape so long as the middle portion 150 is located substantially along the longitudinal centerline 160, 170 of at least one of the top and bottom portions 130, 140. The boom 80 also includes a primary coupling 180 at a first-end portion 190 of the boom 80 and a secondary coupling 200 at a second-end portion 210 of the boom 80. The primary coupling 180 includes a boss 220 that is formed as an integral part of the boom 80 and is positioned between the top and bottom portions 130, 140, adjacent with the middle portion 150. The boss 220 allows for the attachment of the boom 80 with the rear-end portion of the frame 10. The secondary coupling 200 includes bifurcated legs 230, 240, a first boss 250, and a second boss 260, all of which are formed as an integral part of the boom 80. The first boss 250 is positioned at the second-end portion 210 of the boom 80 adjacent to one of the bifurcated legs 230 of the boom 80 and the second boss 260 is positioned at the second-end portion 210 of the boom 80 adjacent to the other bifurcated leg 240. The first and second bosses 250, 260 allow for the attachment of the boom 80 with the stick 90.

[0014] Further, the boom 80 includes top and bottom mounts 270, 280 formed as an integral part of the boom 80. The top mount 270 includes a top flange 290 positioned on the top portion 130 and a boss 300 formed on the top flange 290. The top mount 270 is positioned between a midpoint 310 of the boom 80 and the second-end portion 210. The bottom mount 280 includes a bottom flange 320 positioned on the bottom portion 140 and a boss 330 formed on the bottom flange 320. The bottom mount 280 is positioned so that the boss 330 is positioned near the midpoint 310 of the boom 80.

[0015] Finally, the body 124 of the boom 80 includes a curvilinear portion 340 positioned between the midpoint 310 of the boom 80 and the first-end portion 190. The curvilinear portion 340 is usually positioned a predetermined distance D₁ from the first-end portion 190 and a predetermined distance D₂ from the second-end portion 210 wherein the distance D₂ is greater than D₁. Alternatively, the curvilinear portion 340 could be positioned so that the distance D₁is greater than the distance D₂. The curvilinear portion 340 is formed to position the first-end portion 190 at an inclination of between 20 and 90 degrees with respect to the second-end portion 210 as shown at 350. It should be understood that the angle of inclination 350 of the first end portion 190 with respect to the second-end portion 210 could be different depending upon the particular work machine on which the boom 80 is attached and the ranges referenced above are not meant to limit the angle of inclination of the first-end portion with respect to the second-end portion.

[0016] An alternative embodiment is depicted in FIG. 3 with reference numbers of previous Figures being used to identify similar components therein. The boom 80 is manufactured from various components through an assembly process and has a first-end portion 400 and a second-end portion 410. The boom 80 includes top and bottom plates 420, 430, and a middle plate 440 welded between and substantially perpendicular with longitudinal centerlines 450, 460 of the top and bottom plates 420, 430, to define a body 124 similar to that of FIG. 2. The top and bottom plates 420, 430 each include bifurcated legs 470, 480, 490, 500 positioned at the second-end portion 410. The boom 80 also includes a primary coupling 510 defined at the first-end portion 400 and a secondary coupling 520 defined at the second-end portion 410 of the boom 80.

[0017] The primary coupling 510 is formed by welding a boss 530 between and with the top and bottom plates 420, 430 and with the middle plate 440. When the middle plate 440 is welded with the top and bottom plates 420, 430, the top and bottom plates 420, 430 are longer than the middle plate 440 and extend beyond the middle plate 440 at the first-end portion 400 thus creating a pocket 540. The boss 530 fits into the pocket 540 and is welded with the top, bottom, and middle plates 420, 430, 440. The primary coupling 510 pivotally attaches the boom 80 with the rear-end portion of the frame 10.

[0018] The secondary coupling 520 is formed by positioning a curved, outwardly extending intermediate plate 550 between the bifurcated legs 470, 480, 490, 500 and welding it thereto. A first boss 560 is welded between one of the bifurcated legs 470, 490 of the top and bottom plates 420, 430 and with the intermediate plate 550, and a second boss 570 is welded between the other bifurcated legs 480, 500 of the top and bottom plates 420, 430 and with the intermediate plate 550. The secondary coupling 520 pivotally attaches the boom 80 with the stick 90.

[0019] The boom 80 further includes a top mount 580 and a bottom mount 600. The top mount 580 is welded with the top plate 420 and is positioned between a midpoint 590 of the boom 80 and the second-end portion 410. The bottom mount 600 is welded with the bottom plate 430 and is positioned substantially at the midpoint 590 of the boom 80. The top and bottom mounts 580, 600 include top and bottom flanges 610, 620 that are welded with the top and bottom plates 420, 430, respectively. Each of the top and bottom flanges 610, 620 include apertures (not shown) therethrough, and each such aperture has a boss 630, 635, 640, 645 welded to each side thereof.

[0020] Finally, the boom 80 includes a curvilinear portion 650 that is similar to the curvilinear portion 340 in FIG. 2. The curvilinear portion 650 is formed before welding of the components by bending the top, bottom, and middle plates 420, 430, 440 and then welding them together. Further, although welding is mentioned as the means for attaching the various components of the boom 80 together in FIG. 3, it should be understood that any suitable means, such as bonding or the like, may be used to achieve similar results.

INDUSTRIAL APPLICABILITY

[0021] During normal operation, the implement 100, stick 90, and boom 80 work in unison to effectively perform work functions, such as digging a hole or moving large amounts of material. During this sort of operation, forces are transmitted through the implement 100 to the stick 90, to the boom 80, and ultimately to the frame 10.

[0022] In the embodiment depicted in FIG. 2, the boom 80 is manufactured so that the top, bottom, and middle portions 130, 140, 150 form the body 124 as a unitary member. Additionally, the primary and secondary couplings 180, 200 and the top and bottom mounts 270, 280 are manufactured as part of the unitary boom 80. The manufacturing can be accomplished by casting the boom 80, or another suitable manufacturing process. The casting process reduces the requirement of assembling and attaching four supporting structures required for the box boom, reducing the time and cost required to manufacture the boom 80. The reduction of the four supporting structures also reduces the overall weight of the boom 80. Further, the reduction of welding reduces weld-induced stress and fatigue concerns. Finally, the boom 80 of FIG. 2 has a cross sectional I-shape that provides sufficient support for the compressive and tensional forces applied to the boom 80 during normal operation by distributing such forces throughout the boom 80 structure. The boom 80, therefore, is able to handle heavy-duty applications with a reduced weight configuration.

[0023] Alternatively, as depicted in FIG. 3, the boom 80 can be manufactured from various components while having the same I-shape structure as that in FIG. 2. The middle plate 440 is welded to the top and bottom plates 420, 430 along the longitudinal centerline of the top and bottom plates 450, 460. The primary coupling 510 is assembled and welded to the first-end portion 400, and the secondary coupling 520 is assembled and welded to the second-end portion 410. Finally, the top and bottom mounts 580, 600 are welded to the top and bottom plates 420, 430, respectively. Even though there are more components than the design in FIG. 2, the manufacture of the boom 80 still reduces the time and cost because it has fewer components to assemble than other boom designs. Further, because there are fewer components to assemble and attach there is less welding required, therefore, the weld-induced stress and fatigue concerns are reduced. Again, as with the boom 80 of FIG. 2, heavy-duty applications are achieved with a reduced weight configuration.

[0024] As can be see from the descriptions above, the boom 80 can be manufactured as a unitary member or with fewer components that the box boom design requiring four supporting structures. This causes the boom 80 to be less expensive to manufacture, less expensive to operate, and reduces stress and fatigue thereof. Further, the general I-shape structure provides a stronger boom 80 with a reduced weight for increased operational advantages.

[0025] Other aspects, objects and advantages of the invention can be obtained from a study of the drawings, the disclosure and the appended claims. 

What is claimed is:
 1. A structural member of a work machine, the structural member having first and second-end portions, comprising: a body having a top portion, a bottom portion, and a middle portion, the top and bottom portions having longitudinal centerlines, the middle portion positioned between and substantially perpendicular with the top and bottom portions and positioned substantially at the longitudinal centerline of at least one of the top and bottom portions; and a primary coupling formed with the body at the first-end portion and extending from at least one of the top, bottom, and middle portions.
 2. The structural member of claim 1, wherein the body has a substantial I-shaped cross-section.
 3. The structural member of claim 2, wherein the top, bottom, and middle portions consist of respective top, bottom, and middle plates.
 4. The structural member of claim 3, further including a secondary coupling formed with the body at the second-end portion and extending from at least one of the top, bottom, and middle plates.
 5. The structural member of claim 4, wherein the primary and secondary couplings extend from each of the top, bottom, and middle plates.
 6. The structural member of claim 1, wherein the body has a curvilinear portion positioned a predetermined distance from the first-end portion and a predetermined distance from the second-end portion, the predetermined distance from the second-end portion being greater than the predetermined distance from the first-end portion.
 7. The structural member of claim 1, wherein the structural member has a midpoint defined between the first and second-end portions and further includes top and bottom mounts wherein the top mount is positioned between the midpoint and the second-end portion and the bottom mount is positioned substantially at the midpoint.
 8. A work machine, comprising: a frame; a first member having first and second end portions, a top portion, a bottom portion, and a middle portion, the top and bottom portions having longitudinal centerlines, the middle portion positioned between and substantially perpendicular with the top and bottom portions and positioned substantially at the longitudinal centerline of at least one of the top and bottom portions; a second member; a primary coupling defined at the first-end portion of the first member for pivotable attachment with the frame; and a secondary coupling defined at the second-end portion of the first member for pivotable attachment with the second member.
 9. The work machine of claim 8, wherein the first member has a substantial I-shaped cross-section.
 10. The work machine of claim 8, wherein the first member is one of a structural member and a stick and the second member is one of a structural member, a stick, and an implement.
 11. The work machine of claim 8, wherein the primary coupling and secondary coupling are formed as an integral part of the first member.
 12. The work machine of claim 8, wherein the top, bottom, and middle portions of the first member consist of respective top, bottom, and middle plates.
 13. The work machine of claim 12, wherein the top and bottom plates include bifurcated legs at the second-end portion, the primary coupling includes a first boss adjacent the middle plate and attached between the top and bottom plates, and the secondary coupling includes an intermediate plate attached between the top and bottom plates, and including a second boss adjacent the intermediate plate and attached between one of the bifurcated legs of the top and bottom plates and a third boss adjacent the intermediate plate and attached between one of the other bifurcated legs of the top and bottom plates. 